This invention relates to an outdoor enclosure or cabinet (referred to as a service protection enclosure) to be installed during the construction of a remote wireless telecommunications site (e.g., a cellular telephone "cell site") or the like, for housing the AC (alternating current) power termination connections, AC power distribution panel and circuit breakers, for housing RF (radio frequency) transmission cable terminations, and for housing telephone equipment for the termination of the telephone lines (referred to as "telco" lines) leading to and from the site. Importantly, the service protection enclosure of the present invention provides single point grounding for protecting the radio equipment and RF, telco and AC power terminations within the enclosure from lightning strikes and low power voltage transient signals often present on the telco lines, AC power lines and on the RF cables that interfere with communications transmissions to and from the site. In this manner, all connections and lines to the radio equipment are provided with clean, filtered power or signals. This invention further relates to a method of constructing such a remote wireless telecommunications site utilizing a service protection enclosure, as above-described.
In recent years, there has been a rapid growth of the telecommunications and wireless communications industry. This rapid growth has meant that networks of wireless telecommunications transceiver sites have been constructed across the U.S. and around the world. This has been particularly true in the cellular telephone industry where cell sites must be constructed to provide a network of overlapping service areas by each cell site such that cellular service may be offered throughout the service area to be served by the network. Typically, a cell site will have a tall tower for supporting the antennas for the cell site. In addition, provision must be made at the cellsite for housing the radio equipment, for interconnecting the cellsite to the telephone or telco network, and for supplying AC power to the cell site. This has typically required the construction of a shelter at the cellsite to house this equipment and to provide an area where the various services may be connected with one another.
However, particularly in metropolitan areas, it is usually necessary to obtain approval under the zoning laws of the particular community in which the cell site is to be constructed. There has been considerable opposition to the construction of such cell sites, due primarily to the tall tower required and the utilitarian appearance of the shelter enclosing the necessary equipment at the cell site. It has thus been a long-standing problem of obtaining zoning approval for the construction of such cell sites.
In recent years, there has been a trend to house the radio equipment at the cell site in an outdoor equipment cabinet, with the other services (e.g., AC power and telco interconnections) housed in other outdoor cabinets. Generally, the cabinet used to house the radio equipment is too small to house the other equipment. While this trend of housing the equipment in separate enclosures or cabinets has eliminated the need for a shelter, it has resulted in multiple cabinets and it has increased the complexity of the construction process in installing the separate cabinets and the equipment therein, in interconnecting the equipment in the separate cabinets, and in providing adequate grounding in eliminating ground loop currents and voltages between the equipment in the separate cabinets.
There have, however, been safety and security concerns for housing all of the equipment jointly with the radio equipment in a single cabinet or enclosure. It is generally not good security or safety practice to allow power company personnel access to the radio equipment or to allow the telco personnel access to the AC power equipment. Further, there have been grounding problems and RF interference problems when the AC power terminations and the telco terminations were housed in close proximity to the radio equipment.
In addition, there has been a long-standing problem of how best to protect the equipment at such a cellsite from voltage surges, lightning strikes, and from transient voltages, and how to best protect this equipment from any currents that may flow across the terminals of the equipment caused by any difference in the grounding potentials between the remotely located equipment where such remotely located equipment is grounded to different points within the site.
In the construction of cell sites, prior to the present invention, there was typically a problem in scheduling different trades to perform their work at the cell site. Often, a trade (e.g., those craftsmen who connect the RF coax cables to the radio equipment) cannot perform their job at the site until other work (e.g., installation of the radio equipment in its cabinet) has been done. This is particularly true when the various equipment must be installed in different enclosures or within a shelter. Further, those skilled in this field will recognize that there may be long lead times required for certain equipment to be delivered to the site. Heretofore, these long lead time items (especially the radio equipment) would adversely impact the scheduling of the installation of the other equipment at the site.